BRONCHITIS 589 



branches of the trachea are known as the bronchi, and inflamma- 

 tion affecting the bronchi is known as bronchitis or cold in the 

 chest. 



Causes. — The causes of bronchitis are about the same as those 

 for cold in the head and sore throat. As a matter of fact, the in- 

 flammations of the bronchi usually follow an attack of cold in the 

 head or laryngitis. Exposure to cold northeast winds, especially 

 when overheated, as when coming out of a steaming nest beneath 

 straw-stacks or manure piles, is one of the most common causes of 

 the disease. Accordingly, this disease is especially frequent during 

 the winter and spring months. 



Animals which are shipped in open stock cars during the winter 

 months very often develop a severe bronchitis. Fat hogs are very 

 easily overheated by running or driving, and as a result develop 

 an inflammation of the bronchial tubes. Dipping of hogs in cold 

 weather is another very common cause for the disease. Fluids 

 entering the wind-pipe when drenching a sick hog may set up a very 

 severe form of bronchitis. 



As in the case of other diseases of the respiratory tract, this con- 

 dition may be produced by inhalation of dust or of irritating chem- 

 ical vapors. Another somewhat frequent cause of bronchitis is the 

 presence of lung worms. Heart disease is usually comphcated by 

 the presence of a chronic form of bronchial inflammation. 



Symptoms. — Bronchitis is ushered in by a loss of appetite, dul- 

 ness, and a feverish condition. Cough is an early and pronounced 

 symptom. This cough at first is of a short, dry character, but later 

 becomes more moist, and is accompanied by a discharge of mucus 

 from the nose and mouth. In the cases that are due to lung worms 

 some of the parasites may be coughed up. 



The breathing is somewhat rapid, and may be of rather a noisy 

 character. The animal has an unthrifty appearance, has a tend- 

 ency to remain hidden in its nest, and, if forced to move about, a 

 spell of coughing is brought on. If the ear is placed on the chest 

 wall, loud whistling sounds known as rales can be heard. 



In the chronic form of bronchitis the principal symptom is the 

 cough, which is especially noticeable when the animal comes out of 

 its sleeping quarters in the mornings. The hog has a rather un- 

 thrifty appearance and does not gain in weight as it should. 



